1. Field of the Invention
The present invention relates to apparatus for processing image data, a method of processing image data and a computer-readable medium.
2. Description of the Invention
The digitisation of image processing has enabled many new image manipulation techniques to be developed. Available digital processing effects include a process of color warping, in which color attributes of an image, or area of an image, can be modified in some way. Common uses for such a technique are compensation for camera or film color distortions and special effects.
Many image processing systems provide control over color through the use of gamma correction curves. A gamma correction curve define transfer functions that are applied to red, green and blue image data values, in such a way that a color transformation may occur. However, manipulation of such curves to produce satisfactory results is extremely difficult. In the case of creating special effects, the lack of intuitive feel of such an approach makes achieving useful results extremely difficult.
From a mathematical perspective, many systems provide color transformations defined in terms of matrices. Matrices may be used to define arbitrary transformations in color space, just as they are used in the more familiar world of computer modelling and computer-aided design. However, although such techniques theoretically provide an enhanced level of control over color space, and have the potential to facilitate useful color warping tools, the lack of an intuitive relation between the mathematics and the effect upon the colors of an image makes these techniques difficult to use.